气候变化背景下麦田沟金针虫爆发性发生为害

近年华北地区大面积推行保护性耕作措施和作物秸秆粉碎还田，冬小麦与夏玉米一年两熟连续轮作种植，为沟金针虫创造了有利的取食和栖息环境。地处华北北部的中国气象局固城农业气象野外科学试验基地2018—2019年秋季、冬季、春季气温出现了冷暖交替，尤其最低气温显著偏高，诱发麦田沟金针虫爆发性发生为害。据春季麦田挖土调查，虫口密度最高达144头·m-2，虫口重量最重达18.764 g·m-2。58个调查点达防治指标5头·m-2占98.27%。拔节-收获期调查虫口密度孕穗期最高，拔节期次之，收获期最低。冬小麦与夏玉米禾本科作物连作种植田间虫口密度达35.3~40.4头·m-2，显著高于前茬大豆、玉米、冬小麦休闲地，且花生地、春玉米地比大豆地虫口密度高5倍多，虫口重量高10倍以上。成熟期虫害麦田测产，籽粒减产36.8%；虫口密度增加10头·m-2，籽粒减产率增加4.824%；虫口重量增加1 g·m-2，籽粒减产率增加3.871%；植株虫害率增加10%，籽粒减产率增加11.587%。

The Outbreak and Damage of the Pleonomus Canaliculatus in Wheat Field Under the Background of Climate Change

In recent years, with the large-scale implementation of conservation tillage measures and crop straw crushing in North China, the winter wheat and summer corn are planted in two crops per year, creating a favorable environment for feeding and habituating for the Pleonomus canaliculatus. As the temperature in autumn, winter and spring of Gucheng Station in Hebei Province alternates between cold and warm from 2018 to 2019, the minimum temperature is significantly higher, inducing the explosive occurrence of the Pleonomus canaliculatus in the wheat field. According to the investigation of spring wheat field excavation, the maximum density of insect population is 144 heads·m-2, the maximum weight of insect population is 18.764 g·m-2. Among 58 investigation points, densities of 57 points exceed 5 heads·m-2, which calls for control measures. The density of insects in the jointing-harvest period is the highest during the booting period, followed by the jointing period, and that of the harvest period is the lowest. The oldest larvae have a maximum length of 34.68 mm, and a maximum width of 4.9 mm, 4.68 mm longer and 0.90 mm wider comparing to existing record respectively. The density of insect populations in the continuous cropping winter wheat and summer maize gramineous crops is 35.3 to 40.4 heads·m-2, which is significantly higher than that of soybean, corn, and winter wheat recreation grounds. The peanut and spring corn lands are more than 5 times higher than the soybean insect population density, and the weight of insect population is more than 10 times higher. Yield measurement in mature wheat fields shows the grain yield is reduced by 36.8%. When the insect population density increases by 10 heads·m-2, grain yield decreases by 4.824%. When insect population weight increases by 1 g·m-2, grain yield reduction increases by 3.871%, and 10% increase of plant pest will make the grain yield reduction rate increase by 11.587%.